Auditory-visual multisensory enhancement in a vertebrate command neuron

OTERO CORONEL, SANTIAGO; MEDAN, VIOLETA

Chicago

Congreso; Neuroscience 2019; 2019

Society for Neuroscience

Different sensory systems provide animals with valuable information that allows them to identify possible threats and react accordingly. In fish, the Mauthner cell receives inputs from the visual and auditory systems and commands the C-start escape response. By combining optic tectum and auditory stimulation with in vivo intracellular recordings of the Mauthner cell in goldfish (Carassius auratus), here we show that multimodal stimuli produce higher responses than their unimodal counterparts. We also address how the linearity of the multisensory enhancement depends on the temporal order of the unimodal stimuli, as well as the duration and frequency of the tectal stimulus.Multimodal responses to a sound pip before (-50 ms), simultaneously or after (50 ms) a single 1 ms-tectal pulse are higher than those evoked by the best unimodal stimulus. To obtain a multisensory linearity index (MLI) we divided the peak multimodal response by the sum of the peak unimodal responses. We found that when presenting a sound pip 50 ms before a single tectal pulse, the mean (± SEM) MLI was 0.84 ± 0.02, N=23 and significantly lower than when presenting the sound pip simultaneously (0.91 ± 0.02, N=23, p=0.04) or 50 ms after tectal stimulation (0.92 ± 0.02, N=12, p=0.04).Increasing the duration (1 to 200 ms) of a 60 Hz tectal train produced higher unimodal responses. However, a sound pip presented at the end of the tectal train produces multimodal responses that are equally effective for all train durations. Accordingly, the MLI for a pip after a single 1 ms-tectal pulse was significantly higher (0.91 ± 0.02, N=23) than for the longest tectal train (200 ms: 0.67 ± 0.05, N=13, p